The present invention relates to an exhaust gas purifying device, and more particularly to an improved assembly of a thermal reactor.
In general, the recombustion chamber of a thermal reactor is used at a high temperature in order to achieve a satisfactory effect of recombustion. Even when heat is insulated by covering with a heat insulting layer an inner core forming the recombustion chamber, the temperature of the surface of the case of a thermal reactor becomes high. Where the thermal reactor is mounted on a vehicle, the surface temperature should desirably be low so as to prevent other components from being adversely affected by the heat. For this reason, the thermal reactor is cooled by means of a fan for cooling an engine body as is provided in front of the engine body. It is usual, however, that the thermal diffusion in the case surface differs greatly in dependence on areas of the surface and that the surface temperature of the case varies in dependence on the areas. The difference of the thermal diffusion is attributed to the manners of flow of and exposure to wind from the cooling fan. Generally, the case surface temperature is much higher at the hinder part of the vehicle than at the fore part. In the case surface, a higher temperature portion and a lower temperature portion arise, and the extents of thermal expansion therefore differ. This brings about such disadvantage that the case, gasket etc. of the thermal reactor are prone to damage.